我如何在Swift中声明typedef

如果我需要Swift中的自定义types，那么我可以inputtypedef ，我该怎么做呢？ （类似于一个闭包语法typedef）

Answer 1

关键字typealias用于代替typedef

 typealias CustomType = String var customString:CustomType = "Test String" 

Answer 2

添加到上面的答案：

“typealias”是使用的是与typedef类似的函数的关键字。

  /*defines a block that has no input param and with void return and the type is given the name voidInputVoidReturnBlock*/ typealias voidInputVoidReturnBlock = () -> Void var blockVariable :voidInputVoidReturnBlock = { println(" this is a block that has no input param and with void return") } 

要使用input参数创buildtypedef，语法如下所示：

  /*defines a block that has input params NSString, NSError! and with void return and the type is given the name completionBlockType*/ typealias completionBlockType = (NSString, NSError!) ->Void var test:completionBlockType = {(string:NSString, error:NSError!) ->Void in println("\(string)") } test("helloooooooo test",nil); /*OUTPUTS "helloooooooo test" IN CONSOLE */